Publish theme snapshots through IPC from explicit live state

crates/ferese-theme/tests/theme_wire.rs

@@ -0,0 +1,63 @@
+use ferese_ipc::theme::Snapshot;
+use ferese_theme::service::fallback;
+use serde_json::{Value, json};
+
+fn fixture() -> Value {
+    serde_json::from_str(include_str!("fixtures/theme-v2.json")).unwrap()
+}
+
+#[test]
+fn default_snapshot_preserves_wire_values_and_environment_wallpaper() {
+    let mut snapshot = fallback();
+    let wallpaper = Some(ferese_config::default_wallpaper().into());
+    assert_eq!(snapshot.theme.tokens.background.path, wallpaper);
+    assert_eq!(snapshot.presented.tokens.background.path, wallpaper);
+    snapshot.theme.tokens.background.path = Some("<wallpaper>".into());
+    snapshot.presented.tokens.background.path = Some("<wallpaper>".into());
+    assert_eq!(serde_json::to_value(snapshot).unwrap(), fixture());
+}
+
+#[test]
+fn older_snapshots_supply_catalog_but_explicit_empty_catalog_stays_empty() {
+    let mut value = fixture();
+    value.as_object_mut().unwrap().remove("families");
+    value.as_object_mut().unwrap().remove("fallback_note");
+    let snapshot: Snapshot = Snapshot::decode(value.clone(), ferese_config::families::builtins).unwrap();
+    assert_eq!(snapshot.families, ferese_config::families::builtins());
+    assert_eq!(snapshot.fallback_note, None);
+    value["families"] = json!([]);
+    assert!(
+        Snapshot::decode(value.clone(), ferese_config::families::builtins)
+            .unwrap()
+            .families
+            .is_empty()
+    );
+    value["families"] = Value::Null;
+    assert!(Snapshot::decode(value, ferese_config::families::builtins).is_err());
+}
+
+#[test]
+fn offline_preview_resolves_without_changing_published_values() {
+    let before = fallback();
+    let document = ferese_config::Document::parse("theme { mode \"light\"; family \"gruvbox\"; }\n").unwrap();
+    let candidate = ferese_config::theme::resolve(
+        &document,
+        std::path::Path::new("/unused"),
+        "2026-10-02T12:00:00Z".parse().unwrap(),
+        |_| panic!("built-in preview must not read theme files"),
+    )
+    .unwrap();
+    assert_eq!(candidate.theme.appearance, ferese_config::theme::Appearance::Light);
+    assert_eq!(candidate.theme.tokens.colors.surface_base, "#FBF1C7");
+    assert_eq!(before, fallback());
+}
+
+#[test]
+fn complete_snapshots_do_not_resolve_fallbacks_and_future_versions_are_rejected() {
+    let value = fixture();
+    let snapshot = Snapshot::decode(value.clone(), || panic!("unexpected catalog resolution")).unwrap();
+    assert_eq!(serde_json::to_value(snapshot).unwrap(), value);
+    let mut future = value;
+    future["version"] = json!(ferese_ipc::theme::SCHEMA_VERSION + 1);
+    assert_eq!(Snapshot::decode(future, Vec::new).unwrap_err(), "Unsupported theme snapshot version");
+}